A. Technical Field
The present invention relates to a ventilator hub, with means for connecting a ventilator spindle and a substantially cylindrical fastening section with radial adapters for a number of ventilator blades, whereby the fastening section has an inner casing surface.
The invention likewise relates to a reinforcement element for use with a ventilator hub having means for fastening a number of ventilator blades with high tensile strength.
Finally, the invention relates to a method for the production of a ventilator with a ventilator hub.
B. Background of the Invention
Ventilators for underground railways or tunnels and/or closed vehicle buildings such as, for example, underground garages, must work very reliably for very long useful lives at various load conditions and environmental conditions. The installation of ventilators in underground railroads or tunnels or underground garages is typically configured for an operating life of several years or decades. In particular, when ventilators are used as smoke removing ventilators in subways or tunnels by metro or tunnel operators, demands are made on the operability of the ventilator at high temperatures, as they occur, in particular, in cases of fire. Some of the demands are specified by law.
On the other hand, as is generally customary, there is a desire to produce ventilators as cost-effective and material-saving as possible. In general, the basic structure of a ventilator consists of a ventilator hub, to which a number of ventilator blades are attached radially. The ventilator blades are fastened by using fastening means such as, for example, pins.
Given the background of the general demands made on ventilators described above, various ventilator blades are known. To keep the mass low, ventilator hubs are known that consist of solid aluminum or an aluminum alloy. However, their limited usability at temperatures above 300° C., makes ventilator hubs made of aluminum disadvantageous. Because the tensile strength of aluminum decreases substantially at the cited temperatures, so that the aluminum slowly begins to flow. Even specialized aluminum alloys are not able to significantly improve this shortcoming. As a consequence of this disadvantageous property of aluminum, ventilator blades can detach from a ventilator hub made of aluminum at high temperatures such can as they occur, for example, in fires.
Because of this shortcoming of ventilator hubs made of aluminum, high volume smoke removing ventilators, i.e. at high speed and/or with large blade lengths of related art use ventilator hubs made of solid steel. But, ventilator hubs made of steel have the disadvantage of having a very large mass.